title: Intentional overdose with tinzaparin: management dilemmas.
abstract: BACKGROUND
  Low-molecular-weight heparin (LMWH) is increasingly being prescribed for prophylaxis and treatment of thromboembolic diseases. Despite the fact that its therapeutic use is considered to be safe, it can be complicated by major hemorrhage and, in contrast to unfractionated heparin, it can only partially be neutralized by protamine. Recent reports of LMWH overdose illustrate the need for a consensus on its management.
  
  
  OBJECTIVE
  To describe a case of self-poisoning with a very large dose of tinzaparin and discuss management options in patients with LMWH overdose.
  
  
  METHODS
  A 69-year-old woman was brought to the Emergency Department 2 h after injecting herself with 280,000 IU of tinzaparin subcutaneously in an attempt to commit suicide. Despite an unrecordable activated partial thromboplastin time (APTT > 180 s) and prolonged prothrombin time, there was no evidence of active bleeding. She was given an intravenous infusion of 100 mg protamine sulfate and was admitted to the intensive care unit, where further infusions of protamine were administered. Normalization of the APTT occurred 40-50 h post admission, reflecting normal tinzaparin clearance rather than neutralization by protamine. No hemorrhagic complications occurred during her hospitalization except for prolonged bleeding from venipuncture sites.
  
  
  CONCLUSIONS
  In this case of massive tinzaparin overdose, conventional doses of protamine failed to rapidly normalize the deranged coagulation parameters. The favorable clinical outcome suggests that, regardless of the LMWH amount injected, no active treatment is needed in the absence of hemorrhage. This is in accordance with the limited published data concerning cases of overdose with other LMWHs.
authors.affiliation: First Department of Internal Medicine, "Amalia Fleming" General Hospital, Athens, Greece.
authors.forename: Iliana
authors.initials: I
authors.lastname: Balla
authors.affiliation: First Department of Internal Medicine, "Amalia Fleming" General Hospital, Athens, Greece.
authors.forename: Ioasaf
authors.initials: I
authors.lastname: Karafotias
authors.affiliation: First Department of Internal Medicine, "Amalia Fleming" General Hospital, Athens, Greece.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Christopoulos
mesh_terms: D000368:Aged; D062787:Drug Overdose / Q000188:drug therapy*; D005260:Female; D005343:Fibrinolytic Agents / Q000506:poisoning*; D006494:Heparin Antagonists / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000506:poisoning*; D006801:Humans; D011479:Protamines / Q000627:therapeutic use*; D013406:Suicide, Attempted; D000078222:Tinzaparin; D016896:Treatment Outcome
chemical_list: D005343:Fibrinolytic Agents; D006494:Heparin Antagonists; D006495:Heparin, Low-Molecular-Weight; D011479:Protamines; D000078222:Tinzaparin
keywords: heparin; low-molecular-weight heparin; overdose; protamine; tinzaparin